QUROPE Quantum Information Processing and Communication in Europe

Topological insulators are of fundamental and technological importance due to their exotic excitations that allow for robust transport of charges (matter) on the boundary and thus have potential applications in spintronics, quantum computing and spintomics.

The recent production of synthetic magnetic fields acting on electroneutral particles, like atoms or photons, has boosted the interest in the quantum Hall physics of bosons. Adding pseudospin-1/2 to the bosons greatly enriches the scenario, as it allows them to form an interacting integer quantum Hall (IQH) phase with no fermionic counterpart.

Topological order has proven a useful concept to describe quantum phase transitions which are not captured by the Ginzburg-Landau type of symmetry-breaking order. However, lacking a local order parameter, topological order is hard to detect.

The fractional quantum Hall (FQH) effect is one of the most striking phenomena in condensed matter physics. It is described by a simple Laughlin wavefunction and has been thoroughly studied both theoretically and experimentally. In lattice systems, however, such an effect has not been observed, there are few simple models displaying it, and only few mechanisms leading to it are known.

Considerable efforts are currently devoted to the preparation of ultracold neutral atoms in the strongly correlated quantum Hall regime. However, the necessary angular momentum is very large and in experiments with rotating traps this means spinning frequencies extremely near to the deconfinement limit; consequently, the required control on parameters turns out to be too stringent. Here we propose instead to follow a dynamic path starting from the gas initially confined in a rotating ring.

Topologically-protected edge states are dissipationless conducting surface states immune to impurity scattering and geometrical defects that occur in electronic systems characterized by a bulk insulating gap. One example can be found in a two-dimensional electron gas (2DEG) under high magnetic field in the quantum Hall regime. Based on the coherent control of the coupling between these protected states, several theoretical proposals for the implementation of information processing architectures were proposed.

Considerable efforts are currently devoted to the preparation of ultracold neutral atoms in the strongly correlated quantum Hall regime. However, the necessary angular momentum is very large and in experiments with rotating traps this means spinning frequencies extremely near to the deconfinement limit; consequently, the required control on parameters turns out to be too stringent. Here we propose instead to follow a dynamic path starting from the gas initially confined in a rotating ring.